Hoya undulata – Rare Wavy-Leaved Hoya with Ant-Friendly Adaptations

Hoya undulata S. Rahayu and Rodda (2015) is a visually striking epiphytic climber from the tropical forests of Kalimantan (Borneo), known for its wavy leaf edges and occasional formation of domatia — tiny structures that may house ants in nature. With leathery, sculptural foliage and slow, rewarding growth, this rare species thrives in bright, humid indoor spaces. It’s a must-have for collectors seeking unusual leaf structure and natural mutualism traits.
 
● Key Features of Hoya undulata

Wavy-Margined Leaves – Mature leaves reach 7 – 15 cm, with undulated edges, leathery texture, fine surface veining, and a subtle semi-gloss finish.
Ant Domatia – Some leaf bases form pockets that may serve as ant shelters in wild settings — one of few Hoyas with this trait.
Variable Growth Habit – Grows as a slender vine or stays compact depending on support, light, and humidity.
 
● Botanical Context and Native Habitat

Origin – Native to lowland rainforests in Kalimantan, Borneo.
Growth Form – Epiphytic, with aerial roots and twining stems that benefit from vertical support.
Formal Description – Described in 2015 by S. Rahayu and Rodda (Garden Bulletin Singapore).
 
● Indoor Growing Conditions for Hoya undulata

Light – Requires bright, indirect light. Tolerates filtered morning sun or strong artificial grow lights.
Temperature – Optimal range is 22 – 30 °C. Avoid exposure below 15 °C.
Humidity – Thrives above 75%. Essential for leaf health and rooting success.
Watering – Let the top 2 – 3 cm of substrate dry before watering again. Never allow roots to sit in soggy conditions.
Substrate – Use 40% orchid bark, 30% perlite or pumice, and 30% sphagnum or coco chips for excellent aeration.
Feeding – Apply a balanced liquid fertilizer every 4 – 6 weeks. A bloom-boosting feed (higher potassium) can be used occasionally.
 
● Potting, Support, and Growth Behavior

Pot Choice – Use a shallow, breathable pot with drainage holes. Terra cotta works well for airflow.
Support – Provide a moss pole, trellis, or stake to guide vines vertically and encourage fuller growth.
Growth Speed – Moderate grower; expect 5 – 10 cm/month under ideal indoor conditions.
Repotting – Only when root-bound. This Hoya dislikes frequent disturbance.
 
● Propagation and Semi-Hydro Tips

Propagation – Take stem cuttings with at least one node. Root in moist sphagnum, perlite, or LECA under 25 – 28 °C and 80%+ humidity.
Rooting Time – Cuttings typically root in 4 – 6 weeks with consistent warmth and airflow.
Semi-Hydroponics – Can adapt to LECA if transitioned gradually. Keep humidity high and flush regularly to avoid salt buildup.
 
● Flowering Behavior and Peduncle Notes

Though flowering is uncommon indoors, Hoya undulata may produce pale pink to off-white, star-shaped blooms with a slightly fuzzy texture in small umbels. These appear on long-lived peduncles — never remove them, as future blooms often return to the same point.
 
● Common Problems and How to Fix Them

Yellowing Leaves – Often from overwatering or compacted substrate. Improve drainage and reduce frequency.
Browning Leaf Tips – Usually caused by low humidity or mineral-heavy tap water. Use distilled or rainwater.
Leaf Drop – Can occur from inconsistent watering or environmental shocks. Keep light, moisture, and airflow stable.
Fungal Spots – Improve airflow and reduce moisture on leaves. Use a gentle fungicide if necessary.
Pests – Mealybugs, spider mites, scale, and thrips may appear. Treat with neem oil or insecticidal soap early.
 
● Etymology and Naming

The species name undulata comes from Latin, meaning “wavy,” a reference to its distinctive leaf margins. The genus Hoya honors 18th-century British botanist Thomas Hoy.
 
● FAQs About Hoya undulata

Can I grow it in low light? – No. It requires bright, indirect light or grow lights to thrive.
Is Hoya undulata toxic? – Not officially listed as toxic, but like all Hoyas, keep it away from pets prone to chewing.
Will it grow in LECA? – Yes, if transitioned gradually and humidity is kept high.
 
● Order Hoya undulata Today

Bring a rare, sculptural species into your collection. Order Hoya undulata now to enjoy its wavy foliage, ant-adaptive traits, and exotic appeal — perfect for Hoya enthusiasts and rare plant lovers alike.